Facebook, the world's largest Internet social network, has started selling its shares to regular investors in one of the largest-ever stock flotations.

In the first hours after founder and Chief Executive Mark Zuckerberg rang the bell to open trading, Facebook shares traded up 8 percent on the technology-heavy Nasdaq stock exchange.

Zuckerberg was cheered by a crowd of hundreds of employees at Facebook's headquarters in California as he rang the bell remotely for the New York-based Nasdaq.

The stock, priced at $38 per share, was to begin trading under the symbol "FB" on the Nasdaq, giving the leading website $104 billion at its market debut.

Many investors are enthusiastic about the profit potential -- skeptics, however, have raised questions about the company's long-term prospects in the fast-moving social-networking world. Facebook now has some 900 million users worldwide.

The initial public offering (IPO) is expected to give Zuckerberg a net worth of nearly $20 billion.

'Demand Driven By Emotion'

The company was started in a Harvard dormitory room eight years ago, and has been hailed for changing the way people communicate online.

In the IPO, Facebook is selling about an 18 percent stake in the company. Amid high investor interest, Facebook announced this week it would be offering more shares than initially planned.

Arvind Bhatia, a senior research analyst at the U.S.-based Sterne Agee brokerage firm, says after trading begins later on May 18, the share price could skyrocket.

"I think the short-term actions of the stock will be driven more by emotion, will be driven more by just the demand-and-supply economics, you know, not enough shares going public and the demand is several-fold," Bhatia says.

Zuckerberg, who turned 28 on May 14, will remain the largest shareholder. Even after the stock flotation, he will own more than 25 percent of the stock.

He will also continue to control the company, holding more than 50 percent of voting rights.

The IPO will also turn several of the other initial owners into billionaires overnight.

The high-profile company was also the subject of an Oscar-winning Hollywood movie last year, "The Social Network."